Division of Animal Sciences, University of Missouri, Columbia, Missouri, USA.
Mol Reprod Dev. 2021 Jul;88(7):490-499. doi: 10.1002/mrd.23516. Epub 2021 Jun 1.
Glutamine supplementation to porcine embryo culture medium improves development, increases leucine consumption, and enhances mitochondrial activity. In cancer cells, glutamine has been implicated in the activation of mechanistic target of rapamycin complex 1 (mTORC1) to support rapid proliferation. The objective of this study was to determine if glutamine metabolism, known as glutaminolysis, was involved in mTORC1 activation in porcine embryos. Culture with 3.75 mM GlutaMAX improved development to the blastocyst stage compared to culture with 1 mM GlutaMAX, and culture with 0 mM GlutaMAX decreased development compared to all groups with GlutaMAX. Ratios of phosphorylated to total MTOR were increased when embryos were cultured with 3.75 or 10 mM GlutaMAX, which was enhanced by the absence of leucine, but ratios for RPS6K were unchanged. As another indicator of mTORC1 activation, colocalization of MTOR and a lysosomal marker was increased in embryos cultured with 3.75 or 10 mM GlutaMAX in the absence of leucine. Culturing embryos with glutaminase inhibitors decreased development and the ratio of phosphorylated to total MTOR, indicating reduced activation of the complex. Therefore, glutaminolysis is involved in the activation of mTORC1 in porcine embryos, but further studies are needed to characterize downstream effects on development.
谷氨酰胺补充剂可提高猪胚胎培养液的发育水平,增加亮氨酸的消耗,并增强线粒体活性。在癌细胞中,谷氨酰胺被认为可以激活雷帕霉素靶蛋白复合物 1(mTORC1),以支持快速增殖。本研究旨在确定谷氨酰胺代谢(即谷氨酰胺分解)是否参与猪胚胎中 mTORC1 的激活。与 1mM GlutaMAX 相比,3.75mM GlutaMAX 培养可提高胚胎发育至囊胚阶段的水平,而无 GlutaMAX 培养则降低了胚胎的发育水平。当胚胎在 3.75 或 10mM GlutaMAX 中培养时,磷酸化 MTOR 与总 MTOR 的比值增加,在没有亮氨酸的情况下增强,但 RPS6K 的比值不变。作为 mTORC1 激活的另一个指标,在无亮氨酸的情况下,用 3.75 或 10mM GlutaMAX 培养的胚胎中 MTOR 和溶酶体标记物的共定位增加。用谷氨酰胺酶抑制剂培养胚胎会降低胚胎的发育和磷酸化 MTOR 与总 MTOR 的比值,表明复合物的激活减少。因此,谷氨酰胺分解参与了猪胚胎中 mTORC1 的激活,但需要进一步研究来描述对发育的下游影响。